Figure 7. Relationship between [Ca²⁺]_pre and ARR.

A, dependence of ARR on the peak amplitude of [Ca²⁺]_pre elevation. Different symbols represent data obtained from different boutons. B, ARR as a function of [Ca²⁺]_pre (pooled results, 19 boutons). ARRs were normalised to the corresponding RRP size. The dashed line represents the power function fit. C, the delayed response decays faster than the [Ca²⁺]_pre transient. The [Ca²⁺]_pre trace was shifted up for clarity. Dotted lines represent the baselines for IPSCs and [Ca²⁺]_pre. Traces represent the average of five recordings. D, correlation between decay time constants of delayed response (τ_DR) and [Ca²⁺]_pre. Data from 12 boutons. The line represents a linear regression fit. E, estimation of the maximal ARR (ARR_max) and the affinity of the Ca²⁺ sensor (K_AR). Data obtained from two boutons (filled and open squares). Linear regression fits (lines) are based on eqn (2). F, pooled data from 19 boutons. The dashed line is computed according to eqn (2).